Room heater



April28, 1942. H. J. bEN.' MccoLLuM 2,281,106

' ROOM HEATER Filed June 1o,A 1959 3 Sheets-Sheet l April 28, 1942; H.' Jv.-D|:: N. MccoLLuMV 2,281,106,

'ROOM HEATER Filed June l0, 1959 3 Sheets-Sheet 2 Apnl 28,1942.

H. J. DE N. MccoLLUM 2,281,106

ROOM HEATER Filed June l0, 1959 3 Sheets-Sheet 3 heater and an Patented Apr. 28', 1942 `UNITED STATES PATENT OFFICE 2,281,106 y ROOM HEATERy Henry J. De N. McCollum, Evanston, Ill. I Apilication June 1o, 1939, seria1No.27s,421

4 Claims. y (Cl. 12S-110) My invention relates generally to room heaters, and more particularly to heaters of this type having an independent; heat generator.

In general, the heater comprises a heat generator, a radiator, a blower, or-its equivalent-to move a combustible mixture of liquid or gaseous fuel and air through the generator and radiator, an igniter to ignite the mixture, and a fan to circulateethe air in the' room through the radiator and into intimate heat transfer relationship therewith.

It is an object of my inventionto provide an improved room heater which may be easily started, which will continue in effective operation without attention, and which has novel automatic control and safety mechanism. ,l

AAnother object of my invention is to provide such a heater with novel control' and safety mechanism which automatically energizes an igniter, starts the movement of combustible mixture through the combustion chamber, starts the circulation of air through the radiator, and after .the combustible mixture becomes ignited, turns 01T the igniter. l

A further object of my invention is to provide novel control and safety mechanism which turns off the fuel supply if the air circulating fan stops, re-energizes the igniter if the llame becomes extinguished, and stops the draft blower, the air circulating fan, and turns olf the fuel, if the combustible mixture is not ignited within a reasonable time. 'Y

A further object is to provide an improved room heater which is dependable, safe, economical and effective in use and economical tomanufacture. K

Other objects will appear from the.iollowing description, reference being had to the accompanying drawings, in which: a

Fig. 1 is a front elevation of theheater with the' heater casing, combustion vchamber and a portion of the radiator shown in vertical section; Fig. 2 is a vertical sectional view through the heater casing, `fuel valve, and mixing chamber,

the remainder of the elevation; u V

Fig. 3 is a diagrammatic representation of the electrical circuit adapted to be used therewith and Fig. 4 is a diagrammatic representation similar to Fig. 3, but show'ng an alternative mechnism.

The heater, as shown in Figs. 1, 2 and 3 and denoted generally by the numeral I0, is comprised of a fuel and air mixing chamber l2. This heater being shown V)in side mospheric pressure.

mixing chamber is provided with a Venturi throat I4, a gas inlet metering orifice I6 and air inlet openings I8, which are protected by a shield 20. Gas and air are drawn into this chamber and properly mixed to -form tion chamber 24,and is there ignited either by the fire within the chamber or by an igniter 26. If it is desired to use a liquid fuel, a simple carburetor is provided with its outlet connected to the fuel supply line.

Although the igniter may take several forms, I

prefer to use a heating coil of resistance wire,

such as nichrome wire, which is electrically Vheated to a point above the ash temperature of Ycombustion chamber and radiator, a motor driven centrifugal blower 34 is interposed in the exhaust pipe and maintains the whole systembelow at- The radiator 28 is thus heated to a high temperature, and this heat is dissipated into the room by a fan 36 driven by an electric motor 38.

A room heater, as described generally above, very efficient in its operation, and a small installation will heat a comparatively large room.

Because the entire heat producing portion of the system is sealed and operates below atmospheric pressure, carbon monoxide and other noxious gases cannot leak' from the heater. If a leak should develop at any point in the apparatus, a'ir from the room will flow in'to the heater, andif this leak should be sufficient to extinguish the fire, the fuel will be shut off in a manner to be pointed out later.

Since the radiator 28 is designed to operate with an air stream from the fan 36 blowing thereover whenever the radiator is het, any failure of the fan 36, whether caused by a fault in the motor 38 or by some vinterference with the fan blades, may -allow the temperature cfthe radiator and exhaust pipeto become elevated to an unsafe level.

To provide for this contingency, a valve interposed in the fuel line between the fuel air mixingv device l2 and the fuel source. This valve 40 comprises a .metal cup 42 having a threaded inlet opening 44 at its center and a threaded eutletgopening 46 spaced to one side and a combustible mixture` v.which passes through a tube 22 into the combus- 40 isV thereof. The inlet opening 44 is secured to a fuel supply line 48 by means of a nipple 50 and compression coupling 62, while the outlet opening is similarly-connected to the fuel and air mixing device I2 by a tube or pipe 54.

The outward portion of the cup 42 is .provided with a flange 56 which 'supports aflexible diaphragm 58 and an outwardly bowed cover 60. Screws 62 extend through the marginal portion ofthe cover 60 and diaphragm 58 and are threaded into the flange 56 to secure the cup, diaphragm and coverv in assembled relation. An axially movable valve stem 64 extends through central openings 66 and 68 in -thecover 60 and diaphragm 58, respectively. This valve stem B4 is secured to the diaphragm 58 by means of two nuts threaded to the'valve stem and positioned with one on each side of the vdiaphragm and tightened thereagainst to provide an air-tight When at rest, the valve cuts off the inwardly by a compression spring 14 which surrounds Athe valve stem and is positioned between the inner surface of the cover 60 and the dia- V phragm 58.

The shaft of the fan motor 38 is carried on bearings (not shown) which permit considerable axial movement of the shaft under the inluence of the thrust developed by the rotating fan 36. The rear end of this shaft has a portion 16 of reduced diameter -which extends through an opening 18 in one end 'of a lever 80, the'other end 82 of which is hinged at 84 to the lower portion of the valveA cover 60. Somewhat abpve the hinge 84, the lever 80 is hingedly secured to the outward end of the valve stem 64 as by a bolt or pin 86 which extends through aligned openings in the valve stem and lever. y

From the above it will be seen that with the apparatus atrest, the spring 14 will urge' the valve into closed position and the motor shaft forwardly. In this position the fuel supply to the burner is cut off. Now, when the lmotor starts, the reactive force of the revolving fan A36 pushing the air forwardly will urge the motor shaft backward and open the Vfuel valve.

Should the fan stop at any time, the spring again urges the fuel valve into closed position.

In the electrical control mechanism shown in l Fig. 3, a primary circuit-comprises a main line switch||4 which may be used to shut oil the heater for extended periods, a thermostatically controlled mercury tilt switch of conventional are similar, a description of one will suffice as a description of both.

The switch A| 2 4 comprises a |28,'a bottom. blade |30 and a middle blade |32. Each of these blades vis insulated from the others by means of insulating strips or blocks |34 and the whole is bound togetherby screws or rivets extending through insulating tubes (not shown) in a mannerl well known. The top and bottom blades 4|28 and |30, respectively, are resilient;

while the middle blade |32 is composed of a bimetal strip so arranged that its outward end flexes downwardly toward strip |38 as its temperature Each of these strips is provided with one or more contact points at its outwardv end arranged as follows: A contact point |36 on the lower surface of the upper strip |28,'a point |38 normally in contact with point |36 and supported upon a bracket secured to and in electrical contact with the outward end of strip |30, a point |42 on the lower surface of the bi- 'metal strip |32, and a point |44 on strip |30 t adapted to co-operate with point |42, but normally separated therefrom at room temperatures or somewhat thereabove.

The similar elements ofsmilar switch |24' are as follows: top blade |28', lower blade |30',

' bimetal blade |32', insulating spacers 34 top blade contact |36', offset contact |38', oiset contact supporting bracket |40', bimetal blade contact |42 and lower blade contact |44'.

The temperature responsive switch |24 is mounted upon the combustion chamber housing design H6 which'is placed inthe room to be' heated in a position remote from the heater and serves to start and stop the 'heater whenever n tomaintain the room temperature substandeny constaneana the primary mtr e transformer |20.y The transformer is designed pleting a circuit to lgive approxi-'f65 mately seven volts in its secondary '|22, inasmuch f as the secondary circuit includes open contact switches which mayA more safely be utilized at low voltag,

The electrical control circuit depends for its operation upon two similar thermally responsive switches. one |24 mo tedupon the combustion chamber housing the other |24' secured to the igniter housing. Since these two switches by means of a metal bracket |48, which serves to conduct heat from the housing to the bimetal blade |32. The switch |24' is similarly secured in heat conducting relation to the igniter housing so that when the i'gniter 26 is energized it will heat Ythe bimetalblade |32' and deflect its outward end downwardly.

Y' In the circuit, as shown in Fig. 3, one end of the transformer secondary |22 is grounded while the other end is electrically connected by a conductor |50l to switch blade |30. This con` ductor |50 also has a branch |52 leading to switch blade |28'. The top switch blade |28 has a conductor |54 secured thereto leading to the igniter 26, the other side of which is grounded. A conductor |56 connects switch blades |32 and |30', while blade |32' is grounded through the motor of the fan 38 by conductor |58, and through the motor of the blower 34 by means of a branch |60 of the conductor |53.

In operation, the main switch ||4 is closed to put the heater in condition to operate. When the thermostat switch ||6 closes, the transformer primary |18 is.,.energized, thereby producing a current in the secondary |22, conductor |66, switch blade |30, contact bracket |40, contacts '|38 and |36, blade |28',.line |54 and igniter 26. As the igniter temperature increases, the bimetal blade |32' lis heated and deflected until contact |42' touches contact |44',- thus comthrough the transformer 1secondary |22, line |58 and |42', blade |32l and thence to' .ground through lines |68 and fan 38, and through branch |68 and blower 34. This energizes the blower 34 which draws a fuel and -lair mixture through the system, and the fan 38 which blows air over theradiatnr tubes and iins.

As' soon a's the fuel and airmixture starts to ilow through the system, it is vignited by the iguiter 26. The heat thus generated by the comtop switch blade tacts |42 and |44 .similar to switch |24',

A comparable elements of switch strip |32 and reflects it downwardly until con tacts |42 and |44 touch. The closing of concompletes an alternative circuit to the fan 38 and blower 34 through conductor |50, blade |30, contacts |44 and |42, bimetal strip |32, line |58, blade |30', contacts |42 and |44', bmetal blade |32' and lines |68 and |60. On slight additional heating, the additional deflection of bimetal strip |32 urges blade |30 downwardly, and |38, and de-energizing the igniter 26. Additional heating o f bmetal separates contacts |36 and |38'.

Though switch |24 may. be so adjusted that contact points |36 and |38 separate yery soon thus separating contacts |36 blade 32' similarly v blade |88. On the after contact is made between points |42 and |44, the similar switch |24' should be adjusted so that considerable deflection of blade |30' is necessary before points V|36 and |38 separate. This is done so that the bmetal blade |32 will have time to heat and complete one alternate circuit to the fan and blower by closing contacts |42 and |44 before the other alternative fan and blower circuit is opened by separating points |38 and |38'. This delay in the separation of points |36 and |38 may be accomplished by making blade |28' with a slight downward flexure, so that because of its resiliency it will follow blade |30' downwardly for a short distance before separating therefrom.

With the \heater operating as outlined above, should the re become `extinguished for any reason, the bmetal blade |32 will cool and allow the igniter, to become re-energized to ignite the fuel. If the re does not become rekindled, then continued cooling of bmetal strip 32 separates contacts |42 and |44 and cle-energizes the fan and blower motors, thereby shutting olf the heater system with the exception of the igniter circuit. r

When the system is first started and in succession the igniter is energized and later the fan and blower are started, if the fire should fail to start within a reasonable time, continued heating of bmetal strip |32' by the igniter 26 will open contacts |36' and |38', thereby shutting off the fan and blower. This occurs because the lack of heat in the combustion chamber has resulted in the alternate motor circuit not being completed, inasmuch as points |42 and |44 remain separated at room temperatures.

The alternative circuit shown in Fig. 4 has a temperature responsive switch |62 which is excepting that it is proheater |64 for its biheater is placed in Vparvided with an electric met-a1 blade iss. This allel with the igniter and is energized at the.

same time as the igniter. The switch |62, therefore, serves the same purpose as switch |24 and may be used in its place inV the control circuit shown in Fig. 3, if desired. Its advantage is that it heats the bmetal blade more quickly and, therefore, energizes the fan and blower sooner than the switch |24', which cannot act until the igniter housing becomes heated, Aand this heat is conducted to the bmetal blade |32. l

The other elements of switch |62 blade |68, lowerfblade |10,upper blade contact |12, lower blade contact |14, lower blade offset bracket |16, offset contact |18, and bmetal blade contact |80. These elements are similar to the |24' and, there.- fore, need no further description here.

A'second temperature responsive switch |82 replaces switch |24,

heat conducting relation with the combustion chamber housing. blade |84,

This switch has `all upper `a lower blade |86, an intermediate bimetal blade |88, and insulating spacers |90, all similar to comparable elements of switch |24. The contact points are differently arranged, however, and provided which at contact are as follows: The

a contact |96 but at room fourth contact |98 face of blade |86.

The other elements in the 200, a blower 202, an igniter upper blade |84 is with a contact |92 on its lower surface, room temperature normally touches a |94 on the upper surface of the bmetal lower surface of blade |88 secured thereto co-operates'lwith, temperature does not touch, a

secured to the upper surcircuit are a fan 204, and a transformer secondary 206, all similar to comparable elements in Fig. 3.

In this circuit, energization of the transformer secondary 206 produces a current flow through conductor 208, bmetal blade and |92, blade |84, conductor 2 Switch heater |64. igniter 204 and heater |64 |88, contacts |94 I0, igniter 204, and

This energization of the conditions the igniter to ignite the fuel and causes a downward dellectionof switch circuit to the transformer secondary blade |66,

thereby completing a fan -200 and blower 202 through 206, conductor 208, and

a branch 2|2 thereof, switch blade |68, contacts |12 and |18, contact bracket |18, blade, |10, contacts |14and |80, blade which is connected to the |86 and conductor 2|4, fan 200 and blower 202 rin parallel. This conductor 2|4 is also connected to switch blade |86 so that after combustion starts and they bmetal blade |88 becomes warmed, its

downward deection will close contacts |96 and |98 and provide an alternate and blower to provide circuit to the fan energization of these units after contacts |12 and |18 have become separated by continued heating of the bmetal strip |66. This alternate circuit consists of the transformer secondary 206, conductor 208, blade 88, contacts |96 and |98, blade |86, and conductor 2|4', which, as has been` to the fan 200 and blower 202.

explained, is connected As the bmetal blade |88 is heated and deflects points |92 and |94 complete the alternative'fan and blower circuit mentioned above, it separates the contact and de-energizes the igniter 204 and bmetal blade heater |64.

It will be appreciated that the circuit of Fig. 4 operates to accomplish the same control effects as the circuit of Fig. 3, and

that, if desired, the

temperature responsive switch |62 in Fig. 4 may switch |24 of Fig. 3.

From the above be seen that by tact, `the operation be replaced by a switch heated by the igniter, as is description of my heater, it will closing a single electrical conof the heateris initiated and that it will continue to operate automatically under full control. supply should fail, the fan and 11i, for some reason, the fuel blower will be shut off, while if the fan motor should stop, the fuel supply will be shut off and the blower and fan will be de-energized. @If the extinguished, the igniter will start combustion againV and if time combustion does not blower will shut oil'.

While I have shownl embodiment of my invention, apparent to those skilled in the fire should become,y

be re-energ'zed to f i within areasonable r start, the fan and be de-energized and th'e fuelsupply and described a4 particular it will be readily artthat numerous` p 4 ltion disclosed. ythe following variationsl may be made therefrom without departing from the basic principles of the construc- I, therefore, desire to include in claims all lsuch modincations and variations as will be readily apparent to those skilled in the art, and by which substantially the results of my invention may be attained in substantially the same way.

l. In a heater of the class described, a Vradiator having inlet and outlet sides, a combustion chamber connected to the radiator inlet side, an exhaust pipe connected to the outlet side of the radiator, an air circulating means connected to the exhaust pipe to maintain said radiator and combustion chamber below atmospheric pressure,

lmeans to supplyfuel to the combustion chamber under the influence of the air circulating means, a fan to blow air over the radiator, 'means to mount said fan for longitudinal movement under the reactive influenceV of air forced therefrom, and means to cut oithe fuel supply whenever the fan stops, comprising a valvel means movable into one position to open the valve and into a second position to close the same, said movable means adapted to be actuated by the longitudinal move \ments of said fan.

2. In an internal combustion heater the com- I bination comprising, a fuel supply line, a valve in said line, means movable into one position to open y being free w move translaamaiu along means presence ofsub-'atmospheric pressure in said valve thereof, means for rotating said shaft and said fan, whereby the reactive force of said fan moves said shaft translationally backward when said fan is rotated, means to connect said shaft to said valve whereby backward movement of said shaft opens said valve, and resilient means tdm'ove said shaft forward and to close said valve.

4. In an internal combustion heater the combination comprising a fuel supply line, a valve chamber, in saidline, having an inlet and an outlet, a flexible diaphragm closingone side of said chamber, a valve in said chamber and movable to open and close said inlet, thereby controlling the flow of ,fuel through said line, a stem for moving said valve, said stem passing through said diaphragm and being sealed thereto so that the chamber tendsto cause said diaphragm toclose said valve, a combustion chamber for receiving and burning fuel from said supply line, a heat exchanger for receiving the products of combustion from said combustion chamber, a vacuum producing'device for withdrawing the products ofv combustion from said heat exchanger and for maintaining said heat exchanger, combustion chamber, and fuel supply line under less than atmospheric pressure, a rotatable shaft mounted the valve and into a second position to close the same, a 'fan mounted for backward movement under the reactive i influence of air propelled therefrom, resilient means `biased to move said ian in a forward direction, and means to connect said fan to said movable .means whereby backward movement of said fan Vmoves said movable means into its said one position and forward movement of said fan` moves said movable means into its said second position.

l 3. InL an internal combustion heater the.` com-` bination comprising, a fuel supply line, a valve in said line, a fan mounted upon a shaft, saidl shaft shaft for translationalmovement for limited translational movement along its axis, a fan mounted upon said shaft for blowing air to be heated past said heat exchanger, means for rotating said shaft and said fan, whereby the rotation of said fan produces a reactive force which tends to move said shaft translationally backward, a lever having an arm engaging said therewith, Vfirst pivot means securing said lever in position, second pivot means securing said lever to said stemso that rearward movement of said shaft opens said valve and forward said valve, and resilient means biasing said shaft toward its forward position.

J. DE N. MccoLLUM.

HENRY movement of said shaft closesl 

